The present invention relates to a method and system for solvent extraction. More specifically, the present invention relates to a method and system for disintegrating droplets to form a plurality of much smaller droplets which have a larger combined surface area than the original droplet, which due to the large amounts of interfacial surface area of the plurality of smaller droplets, solvent extraction operations are enhanced.
Many commercial solvent extraction systems are known. These systems are limited by the mass transfer rates of one or more chemical species between a continuous phase and a dispersed phase. Parameters limiting the mass transfer rate include surface area, convection, diffusion through each of the two phases, reaction rate and differences in chemical activity of the species in the two phases. Diffusion and chemical activity are defined by the system in use. The reaction rate is chemical in nature and convection and surface area are physical problems.
Two major problems which limit the use of solvent extraction in industrial applications are the efficient creation and control of mass transfer surface area. This surface area is merely the surface area of the substance from which a solvent is to be extracted. In practice, interfacial mass transfer surface area is usually created by a form of mechanical agitation. Generally, this mechanical mixing is used to create small droplets with high surface area per unit volume as well as convection past the droplets. This mixing requires the bulk movement of the continuous phase, thus decreasing the efficiency of the process. As the system requires an energy input into the bulk of each liquid phase, energy is inefficiently used in such systems. In addition, agitation may create emulsions in the mass transfer apparatus which prove to be hard to characterize and which may prove difficult to control during phase disengagement. Also, the formed droplets are difficult to coalesce and can result in a significant increase in residence time in the vessel. Furthermore, mechanical mixers can break down causing problems and delays.
Accordingly, a need in the art exists for a effective and efficient solvent extraction method and system. This method and system should not require high energy inputs as is necessary in prior art systems and should avoid the foregoing problems.